disk/aio: Refactor AIO code

Move all AIO code to a separate file, disk/aio.c, to remove as much
#ifdefs as possible. Split the raw read/write disk ops into async and
sync, and choose which ones to u

disk/aio: Refactor AIO code

Move all AIO code to a separate file, disk/aio.c, to remove as much
#ifdefs as possible. Split the raw read/write disk ops into async and
sync, and choose which ones to use depending on CONFIG_HAS_AIO. Note that
we fix raw_image__close() which incorrectly checked CONFIG_HAS_VIRTIO
instead of CONFIG_HAS_AIO, and closed an unitialized disk->evt. A
subsequent commit will complete this refactoring by fixing use of the
'async' disk attribute.

Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

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provide generic read_file() implementation

In various parts of kvmtool we simply try to read files into memory,
but fail to do so in a safe way. The read(2) syscall can return early
having only part

provide generic read_file() implementation

In various parts of kvmtool we simply try to read files into memory,
but fail to do so in a safe way. The read(2) syscall can return early
having only parts of the file read, or it may return -1 due to being
interrupted by a signal (in which case we should simply retry).
The ARM code seems to provide the only safe implementation, so take
that as an inspiration to provide a generic read_file() function
usable by every part of kvmtool.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

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kvm tools: Restart io_submit if it returns EAGAIN

Keep trying if io_submit returns EAGAIN. No need to fail the request.

Signed-off-by: Asias He <asias.hejun@gmail.com>
Signed-off-by: Pekka Enberg <

kvm tools: Restart io_submit if it returns EAGAIN

Keep trying if io_submit returns EAGAIN. No need to fail the request.

Signed-off-by: Asias He <asias.hejun@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

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kvm tools: move read-write.c to util/

read-write.c contains no kvm related code, it is just a lib.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Pekka Enberg <penberg@kernel.or

kvm tools: move read-write.c to util/

read-write.c contains no kvm related code, it is just a lib.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

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kvm tools: Add aio read write functions

This patch adds basic native vectored AIO functions.

These functions should be optimized to process multiple io
requests at once.

Signed-off-by: Sasha Levin

kvm tools: Add aio read write functions

This patch adds basic native vectored AIO functions.

These functions should be optimized to process multiple io
requests at once.

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

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kvm tools: Use writev() in xwritev()

This patch fixes a typo in xwritev(). Luckily the function is not used so the
problem is only latent. Spotted during code review.

Cc: Sasha Levin <levinsasha928

kvm tools: Use writev() in xwritev()

This patch fixes a typo in xwritev(). Luckily the function is not used so the
problem is only latent. Spotted during code review.

Cc: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

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kvm tools: Fix includes for preadv/pwritev

"bornto befrag <born2befrag@gmail.com>" writes:

> When i compile i kvm native tool tools/kvm && make i get this
>
> CC read-write.o
> cc1:

kvm tools: Fix includes for preadv/pwritev

"bornto befrag <born2befrag@gmail.com>" writes:

> When i compile i kvm native tool tools/kvm && make i get this
>
> CC read-write.o
> cc1: warnings being treated as errors
> read-write.c: In function ‘xpreadv’:
> read-write.c:255: error: implicit declaration of function ‘preadv’
> read-write.c:255: error: nested extern declaration of ‘preadv’
> read-write.c: In function ‘xpwritev’:
> read-write.c:268: error: implicit declaration of function ‘pwritev’
> read-write.c:268: error: nested extern declaration of ‘pwritev’
> make: *** [read-write.o] Error 1

Fix that up by including <sys/uio.h> for preadv()/pwritev().
Reported-by: <born2befrag@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

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kvm tools: Fix iov shifting

Use helper function to remove full iov when 'reading in full'.

Thanks Konstantin Khlebnikov.

[ penberg@kernel.org: fix formatting ]
Signed-off-by: Sasha Levin <levinsas

kvm tools: Fix iov shifting

Use helper function to remove full iov when 'reading in full'.

Thanks Konstantin Khlebnikov.

[ penberg@kernel.org: fix formatting ]
Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

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kvm tools: Add scatter-gather variants of IO functions

Added scatter-gather variants of [x,xp][read,write]() and [p]read_in_full().

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-b

kvm tools: Add scatter-gather variants of IO functions

Added scatter-gather variants of [x,xp][read,write]() and [p]read_in_full().

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

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kvm tools: Use pread() and pwrite() in disk-image.c

This patch convert lseek() + read()/write() pairs with pread()/pwrite(). The
performance of running the following command

dd if=/dev/vda of=/de

kvm tools: Use pread() and pwrite() in disk-image.c

This patch convert lseek() + read()/write() pairs with pread()/pwrite(). The
performance of running the following command

dd if=/dev/vda of=/dev/null

in the guest does not show significant performance differences but should be a
net win because of the reduction in system calls.

Signed-off-by: Pekka Enberg <penberg@kernel.org>

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kvm tools: Fix large disk images on 32-bit

Use read()/write() instead of mmap() for virtio block device emulation to
support large disk images on 32-bit.

Reported-and-tested-by: Asias He <asias.hej

kvm tools: Fix large disk images on 32-bit

Use read()/write() instead of mmap() for virtio block device emulation to
support large disk images on 32-bit.

Reported-and-tested-by: Asias He <asias.hejun@gmail.com>
Tested-by: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

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